Grant Support:In part by National Institutes of Health Trauma Center grant #5P50 GM36428, by grant CA 39542, and by the M. Larry Lawrence Foundation. Dr. Jacobs is a recipient of the Robert Wood Johnson Foundation grant 14462.

▪Intervention:Parenteral nutrition was initiated the day after bone marrow transplantation (day 1). The experimental solution was supplemented with L-glutamine (0.57 g/kg body weight per day) and provided estimated requirements for energy and protein. The control solution was a standard, glutamine-free, isonitrogenous, isocaloric formula.

▪Measurements:Nitrogen balance was determined between days 4 and 11 in the initial 23 patients. The incidence of clinical infection and microbial colonization, time until bone marrow engraftment, indices of clinical care, and other data related to hospital morbidity were recorded for all patients.

▪Results:The glutamine-supplemented patients (n= 24) were clinically similar to the controls (n= 21) at entry. Nutrient intake was similar in both groups; however, nitrogen balance was improved in the glutamine-supplemented patients relative to the controls (- 1.4 ± 0.5 g/d compared with - 4.2 ± 1.2;P= 0.002). Fewer experimental patients developed clinical infection (three compared with nine in the control group;P= 0.041), and the incidence of microbial colonization was also significantly reduced. Hospital stay was shortened in patients receiving glutamine supplementation (29 ± 1 d compared with 36 ± 2 d;P= 0.017).